It’s important to have baseline information on any species—with mammals, it is critical to follow individuals for the long term, to get information including health, births, deaths, etc. In our case, studying the society and communication signals is enhanced by having a social context. Knowing whether dolphins are male or female, who they are related to, and what their personalities are really helps us understand the intricacies of their aquatic culture. In a shorter study you would not be able to document long-term relationships. You would also not be able to document the long-term health of the dolphins and also their habitat.
A: I have observed this free-ranging community of dolphins every summer since 1985 on Little Bahama Bank. In 2004 and 2005, our study area was the bull’s-eye for two hurricanes, Frances and Jeanne. After these storms, we documented a loss of 30 percent of both the Atlantic spotted dolphin and bottlenose dolphins in our communities. This was a devastating event for them; we watched as they altered their social behavior and patterns for four years until it finally stabilized.
If hurricanes are getting more frequent and stronger because of climate change, you could say that this did affect them. But the most obvious climate impact occurred in 2012 and 2013. In the summer of 2013, we arrived at our study site and 50 percent of the dolphins were nowhere to be seen. After spending a month looking for them in the far reaches of our study area, we got a report from a dive boat that they thought they saw some of our regular individuals at a site 100 miles away on Great Bahama Bank.
Sure enough, when we reached the new area, there they were, acting normal but in a completely new area. There was already a local resident community of dolphins living there, so we have been monitoring their integration with the locals. But why did they move to this new area after being resident for over three decades in our original study site? After eliminating other possibilities—orcas, noise pollution—we worked through some data from a NOAA site that included chlorophyll-level info (a proxy for plankton/fish) and other environmental data. We concluded that chlorophyll levels in the dolphin area had dropped significantly over some years, and likely resulted in a food crash. We had noticed anecdotally that their nocturnal prey (squid, flying fish) had not been around on the deep-water edge for years. So even this slight adjustment in the food change likely caused the dolphins to move to an analogous ecological site far away.
What caused this drop? We really don’t know. A lot of things have been changing in the Bahamas—a decade of constantly increasing wind speed, changing predominate wind direction and other things yet unmeasured. The sad news is that the recent data also shows a continued drop in the whole northern area of the Bahamas. So our job is to continue monitoring these dolphins and tell the story of climate change and the affect it has on marine mammals.
In our case, noninvasive observations allow us to document their behavior underwater on a regular basis and in some detail. Of course you don’t want them to be too habituated, and you must learn and respect any communication signals they direct at you, because they do use what they have to communicate. There are times that they are in the middle of a big fight and they give us signals that they don’t want us in the water, so we get out. It’s a fine line, but we are very careful about monitoring their disturbance.
I decided years ago that I did not want to take them out the water, even temporarily, to satellite tag them. Of course tagging can give you valuable information you can’t get any other way. But since my priority was to build their trust so that we might observe natural behavior, tagging was out. There are some temporary, less-invasive tags, but nothing that really works for a long period of time that is not attached through a dorsal fin. In 2018 we did have a stranded dolphin from our resident group that was rehabilitated in the Bahamas. In that situation, we did, with multiple research groups, satellite tag and release him, since he was already out of the water. The four months of location data that we got from him was amazing. This male dolphin traveled to parts of the Bahamas that we have not surveyed. He ended up back at home with his group, after his two-month swim-about, so it had a happy ending. So different techniques give you different information, but since the Bahamas is unique in the world for regular clear water observations, I have tried to make use of this situation to observe underwater behavior that is impossible to observe in most parts of the world.
I believe that with all the new cutting edge technology, including Artificial Intelligence tools and Deep Learning, we will eventually come to understand many other species and the complexity of their communication signals. Using that information to communicate across species barriers is perhaps our greater challenge. Do we need to? What could we do together with another species? Humans will need to decide if we want to interact on that level, and if so, can we do it so it is mutually enhancing and beneficial? Or will we just use another species for our own purposes? Myself, I truly believe that we will find other life in our galaxy someday. If we do, are we prepared to assess it and communicate with it for mutual gain? That is the question.
Second, support your local policies and laws that help protect dolphins, including regulations on fishing and pollution (balloons and plastic kill many species from ingestion, for example). Be a voice and speak up if needed in your communities. We must be the voice for many species. And many nonprofits like my own Wild Dolphin Project rely not only on volunteers but memberships to sustain their work, so support who you can.
Today, I continue to admire Sylvia Earle and others who continually bring awareness to ocean issues. And there are many heroes unknown to the larger world that work in small parts of their ocean world who should also be recognized.
Each Sea Hero featured in Scuba Diving receives a Seiko Prospex SRPE05 watch valued at $595. For our December issue, judges select a Sea Hero of the Year, who receives a $5,000 cash award from Seiko to further his or her work. Nominate a sea hero at scubadiving.com/seaheroes.